A recent retrospective cohort study out of China investigated an escalating energy (200 > 300 > 360J) versus fixed energy (200 > 200 > 200 J) defibrillation strategy in OHCA with ventricular fibrillation requiring repeated defibrillations. 

Notes:

• 342 adult patients with OHCA receiving prehospital defibrillation from 2017-2023 
  • *Cheskes et al.'s DOSE-VF for refractory VT/VF published in November 2022
• Defibrillation energy strategy dependent on which biphasic AED was used prehospital; ultimately 64% escalating, 36% fixed low-energy.
• Total 782 defibrillations, mean age 58 years, 80% male

Results:

• Equivalent outcomes after 1st shock in both groups (which makes sense as both groups started with 200J defibrillations)
• More patients in the escalating energy group with VF termination (93% vs 75%, p<0.001) and change to an organized rhythm (64% vs 47%, p<0.001)
• In the refractory VF population (required >2 shocks),  more organized rhythms after 360J than the 3rd 200J defibrillation (35% s 18%, p=0.003).

Caveats: 

• Retrospective
• No assessment of possible shock-related myocardial injury differences between groups
• No commentary on other OHCA management (like anti-arrhythmics)

Bottom Line: For patients with OHCA VF, if the first shock does not succeed, try try again – at a higher dose.

References

• Cheskes S, Verbeek PR, Drennan IR, McLeod SL, Turner L, Pinto R, Feldman M, Davis M, Vaillancourt C, Morrison LJ, Dorian P, Scales DC. Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med. 2022 Nov 24;387(21):1947-1956. doi: 10.1056/NEJMoa2207304.
• Tang H, Wu R, Yin L, et al. Escalating vs Fixed Energy Defibrillation in Out-of-Hospital Cardiac Arrest Ventricular Fibrillation. JAMA Netw Open. 2025 Apr 1;8(4):e257411. doi: 10.1001/jamanetworkopen.2025.7411.